The present invention relates to a system for compensating a heating performance of a continuously-variable-transmission (CVT)-equipped vehicle, and more particularly, to an improvement of the system which achieves the heating-performance compensation requirement by appropriate shift control of the CVT.
Heating, including air conditioning, in the vehicle cabin is typically carried out by using heat generated by the engine. When the engine-coolant temperature is not yet sufficiently high during engine stop and at the initial stage of engine start, the countermeasures should be taken to make heating quickly effective, particularly, in the severe winter.
A heating-performance compensating system which meets such requirement is disclosed in Japanese document P2000-179670A. This system is constructed such that, in the CVT-equipped vehicle in which engine rotation is converted by the CVT and transmitted to the driving wheels, at presence of the heating-performance compensation requirement, a minimum target input rotating speed a at ordinary temperature is increased by a given value ΔN, which is set as a minimum target input rotating speed β at presence of the heating-performance compensation requirement, wherein the CVT is shift-controlled so that an input rotating speed of the CVT does not become smaller than the minimum target input rotating speed β.
With this system, at presence of the heating-performance compensation requirement, an input rotating speed of the CVT is maintained at a value greater than β which is above the minimum target input rotating speed a at ordinary temperature. As a result, a rotating speed of the engine coupled to the input shaft of the CVT can be maintained at a higher value to quickly increase the engine-coolant temperature, obtaining quick enhancement and compensation of the heating performance.